plugin/dnstap: remove config struct (#4258)

* plugin/dnstap: remove config struct

this struct is an uneeded intermidiate to get a dnstap it can be
removed. Remove the dnstapio subpkg: it's also not needed. Make *many*
functions and structs private now that we can.

Signed-off-by: Miek Gieben <miek@miek.nl>

* correct logging

Signed-off-by: Miek Gieben <miek@miek.nl>

plugin/dnstap/io_test.go

@@ -0,0 +1,155 @@
+package dnstap
+
+import (
+	"net"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/coredns/coredns/plugin/pkg/reuseport"
+
+	tap "github.com/dnstap/golang-dnstap"
+	fs "github.com/farsightsec/golang-framestream"
+)
+
+var (
+	msgType = tap.Dnstap_MESSAGE
+	tmsg    = tap.Dnstap{Type: &msgType}
+)
+
+func accept(t *testing.T, l net.Listener, count int) {
+	server, err := l.Accept()
+	if err != nil {
+		t.Fatalf("Server accepted: %s", err)
+	}
+	dec, err := fs.NewDecoder(server, &fs.DecoderOptions{
+		ContentType:   []byte("protobuf:dnstap.Dnstap"),
+		Bidirectional: true,
+	})
+	if err != nil {
+		t.Fatalf("Server decoder: %s", err)
+	}
+
+	for i := 0; i < count; i++ {
+		if _, err := dec.Decode(); err != nil {
+			t.Errorf("Server decode: %s", err)
+		}
+	}
+
+	if err := server.Close(); err != nil {
+		t.Error(err)
+	}
+}
+
+func TestTransport(t *testing.T) {
+	transport := [2][2]string{
+		{"tcp", ":0"},
+		{"unix", "dnstap.sock"},
+	}
+
+	for _, param := range transport {
+		l, err := reuseport.Listen(param[0], param[1])
+		if err != nil {
+			t.Fatalf("Cannot start listener: %s", err)
+		}
+
+		var wg sync.WaitGroup
+		wg.Add(1)
+		go func() {
+			accept(t, l, 1)
+			wg.Done()
+		}()
+
+		dio := newIO(param[0], l.Addr().String())
+		dio.tcpTimeout = 10 * time.Millisecond
+		dio.flushTimeout = 30 * time.Millisecond
+		dio.connect()
+
+		dio.Dnstap(tmsg)
+
+		wg.Wait()
+		l.Close()
+		dio.close()
+	}
+}
+
+func TestRace(t *testing.T) {
+	count := 10
+
+	l, err := reuseport.Listen("tcp", ":0")
+	if err != nil {
+		t.Fatalf("Cannot start listener: %s", err)
+	}
+	defer l.Close()
+
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		accept(t, l, count)
+		wg.Done()
+	}()
+
+	dio := newIO("tcp", l.Addr().String())
+	dio.tcpTimeout = 10 * time.Millisecond
+	dio.flushTimeout = 30 * time.Millisecond
+	dio.connect()
+	defer dio.close()
+
+	wg.Add(count)
+	for i := 0; i < count; i++ {
+		go func() {
+			tmsg := tap.Dnstap_MESSAGE
+			dio.Dnstap(tap.Dnstap{Type: &tmsg})
+			wg.Done()
+		}()
+	}
+	wg.Wait()
+}
+
+func TestReconnect(t *testing.T) {
+	count := 5
+
+	l, err := reuseport.Listen("tcp", ":0")
+	if err != nil {
+		t.Fatalf("Cannot start listener: %s", err)
+	}
+
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		accept(t, l, 1)
+		wg.Done()
+	}()
+
+	addr := l.Addr().String()
+	dio := newIO("tcp", addr)
+	dio.tcpTimeout = 10 * time.Millisecond
+	dio.flushTimeout = 30 * time.Millisecond
+	dio.connect()
+	defer dio.close()
+
+	dio.Dnstap(tmsg)
+
+	wg.Wait()
+
+	// Close listener
+	l.Close()
+	// And start TCP listener again on the same port
+	l, err = reuseport.Listen("tcp", addr)
+	if err != nil {
+		t.Fatalf("Cannot start listener: %s", err)
+	}
+	defer l.Close()
+
+	wg.Add(1)
+	go func() {
+		accept(t, l, 1)
+		wg.Done()
+	}()
+
+	for i := 0; i < count; i++ {
+		time.Sleep(100 * time.Millisecond)
+		dio.Dnstap(tmsg)
+	}
+	wg.Wait()
+}